A conventional planar inverted F antenna (“PIFA”) 100 is shown in FIGS. 1 and 2. PIFA 100 includes a radiating element 102 in spaced relation to a ground plane 104. Radiating element 102 comprises a radiating edge and a non-radiating edge. A shorting post 106 couples radiating element 102 to ground plane 104. A feed 108 supplies radio frequency power to radiating element 102. Radiating element 102 may have a slot 110 placed to quasi-partition radiating element and provide multi band frequency operation. Typically, radio frequency power is supplied through a via 112 in ground plane 104.
Conventionally, PIFA 100 can be tuned to operate at particular frequencies. Tuning is mostly accomplished by altering a length L or a width W of the radiating element. Slot 110 also influences the operating bands. Shorting post 106 and feed 108 also influence the operating frequencies of PIFA 100.
Sometimes, adjusting the length or width of the radiating element is a less than satisfactory solution for tuning the antenna. Additionally, using only a slot in the PIFA top plate typically does not produce enough bandwidth at the upper frequency band. Thus, it would be desirable to provide a multi band planar antenna with additional tuning features and improved bandwidth.